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  <title>Document</title>
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<body>
  <script>
    function Obj(value) {
      this.value = value;
      this.next = null;
    }

    Obj.prototype[Symbol.iterator] = function() {
      var iterator = { next: next };
      
      var current = this;

      function next() {
        if(current) {
          var value = current.value;
          current = current.next;
          return { done: false,value: value};
        }
        return { done: true }
      }
      return iterator;
    }

    var one = new Obj(1);
    var two = new Obj(2);
    var three = new Obj(3);

    one.next = two;
    two.next = three;

    for (var i of one) {
      console.log(i); //1,2,3
    }
  </script>
</body>
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